Thursday, February 3, 2011

The new year brought us the gift of ice this winter as an early thaw with temperatures in the upper 40's and low 50's created considerable snow melt. Immediately following the warm temperatures, cold nights around zero trapped and froze the water that had been melting during the end of December. The result was a nice layer of black ice on many of our putting surfaces. Some greens where completely clear of ice and some where completely covered in ice. #11, #12, #13, and #16 greens where one-hundred percent covered in ice. Greens like #5 and #10 had no ice at all.

What does this mean? Ice cover on a green can cause considerable damage if left on the putting surface for long periods of time. The duration of ice cover, before damage will occur, depends on the species of grass that is under the ice. Ridgeway Country Club's greens are predominately (80% +) Poa annua and the duration of ice cover before damage will occur can vary from 30-60 days depending on the what research article you read. Bentgrass however, can withstand 90 and in some cases 120 days of ice cover. Ice cover produces a scenario where gas exchange is greatly hindered and the grass plant suffocates to death. Anoxia is the term used to describe this phenomenon and is basically turf death due to a lack of oxygen. In order to minimize turf loss due to anoxia, ice cover must be removed to allow the grass plant to breath and receive the oxygen it needs to live.

The above pictures are of the greens after the snow was removed and only the ice was showing.

These last two pictures are after black sand and milogranite was applied to the surface of the ice. The last picture shows melting of the ice after black sand and milorgranite was applied.

Ice on Ridgeway's greens formed on New Year's day and last week we made an effort to remove snow and expose ice to the sun. Remember that ice can cause damage with 30-60 days of coverage on Poa annua greens. Since we where at 20+ days an effort was made to speed up the melting process. Our crew went out and surveyed the greens to see how much of every green was covered in ice. Then snow was removed on only the portions of the greens that had ice cover. After the removal of snow, milogranite (a black organic fertilizer) and black sand where applied directly over the top of the ice. The black color helped absorb the suns heat making ice melt happen quicker. Unfortunately Wednesday and Thursday last week were not sunny as had been predicted by meteorologist but Friday saw a few hours of sun which melted 75-80% of the putting surfaces. Now, only time will tell if any damage to the putting surfaces occurred, more than likely minimal damage occurred because we where able to remove a large percentage of the ice to allow proper gas exchange. My only concern now is the remaining ice in the low spots of some of our greens. An effort to melt this ice will be made sooner than later depending on the weather forecast.

Many important factors must be taken into account when removing or melting ice from greens. One factor is the temperature that is being forcasted immediately following the removal of snow and ice. If snow and ice is removed with cold temperatures or high winds, this can cause other forms of winter injury due to desiccation or direct temperature kill. Snow is a good insulator from the elements, which is why we only removed as much snow as needed to melt ice. A few snow storms since Friday have helped cover the greens to keep them insulated against the wind and cold. Another factor to consider is, what turf species predominates our putting surfaces and what action if any is needed to protect your greens. Because we have a large Poa annua population it is imperative to get the ice off before the 30-60 day window. If we would have mostly bentgrass more than likely no action would be taken because 90 + days of ice cover is needed for problems to arise.

People have asked: why not just use greens covers and we won't have ice? In my experience green covers do little to combat ice coverage. Simply put, if we had green covers we would have ice on top of covers and would have to go through the same process as I explained up above. Green covers work well for other types of winter injury, that being said so does burying greens in a nice layer of sand. We chose to bury our putting surfaces in sand because we could protect all 18 greens, tees, and approaches from dessication. Conversely, we only have enough covers to protect about 8 greens. Applying a nice layer of sand has some nice side benefits as stated by Bob Vavrek in an article written in the USGA green section record, titled "There Is No Time Like The Present."

Vavrek states this about late fall topdressing,

"Late fall topdressing is the poor man’s cover that provides turf fairly good protection from wind desiccation. The often-overlooked benefit of sanding greens before winter is thatch management. Root growth on greens will continue through fall and into winter until the ground freezes. The sand that buffers turf from the damaging effects of winter wind also will help dilute the late fall/early spring organic matter that is recycled into the greens. In effect, pre-winter topdressing provides an effective bridge between the last coring or topdressing operation of fall, and the initial coring or topdressing operation of the following spring. Just how much sand to apply before winter will vary from course to course. Greens maintained at higher heights of cut can accommodate more sand than greens at short heights of cut. When in doubt, it makes more sense to err on the light side of late fall topdressing."

The decision to go with a layer of sand instead of covers was one that was well thought out and took into account many important factors. Because we are in the process of aggressively removing thatch and organic matter from our putting surfaces, the winter topdressing in lieu of covering 8 greens was a no brainer.

One thing research is conclusive on, is that greens that have poor internal drainage, are mostly Poa annua, and/or have trees (especially spruce trees) planted closely to the putting surface are more apt to see winter injury. By improving our sand profile, improving drainage, and removing selected trees around greens we can help combat some of our winter injury woes.

Here are some other articles that discusses ice and other related winter injury.